In casting mills containing one or two casting rolls, it is known that liquid steel comes into contact with the cooled surface of the casting rolls, in order to consolidate thereon. Before the rotating casting roll comes into contact again with the liquid steel, it must be continuously cleaned, in order to prevent any accumulation of metal oxides, slag or other contaminants on the casting-roll surface. Mechanical cleaning devices are used for surface cleaning, such as scrapers, brushes or cleaning belts, with which it is difficult to guarantee consistent cleaning over the entire length of the casting roll. This uneven cleaning has a negative effect on the quality of the cast product. To improve cleaning, there is a known method of distributing a plurality of cleaning devices in sequence along the length of the casting roll, but this gives rise to the risk of gaps forming which impair the surface cleaning. The cleaning devices are also objects which may cause scratching or scraping on the casting-roll surface. These tend to form surface defects on the cast strip. In the casting region, gases and splashes escaping through the liquid steel may contaminate the casting roll surfaces during casting.
From U.S. Pat. No. 5,651,413 it is known that the casting-roll surface can be cleaned by means of a particle/sand blasting device. This involves using one or more spray nozzles distributed over the length of the casting roll. The volume of particles and the spray rate reduces towards the exterior of the spray cone, so that the cleaning is irregular. When several spray nozzles are arranged, areas of contact or overlap arise, which can also lead to irregular cleaning. The particle/sand blasting device which, in addition to the nozzle or nozzles, comprises a receiving container for the sand particles, a return for same, a collecting container, a power supply and a pressurised distributor to send the sand particles back to the nozzle, takes up space. There is also additional dust produced by the atomisation of the particles.